After Pakistan sentenced Indian national Kulbhushan Jadhav to death for "spying", Pakistan Defence Minister Khawaja Asif said on Monday that the execution was a warning for those "plotting" against his country.

Jadhav was arrested in Balochistan in 2016. Pakistan claims that he was a Research and Analysis Wing agent and involved in "subversive activities" in the region.

He added that the death sentence given to Jadhav was a "warning to those plotting" against Pakistan. He said that the country would use constitutional force to act against those who are harming the sovereignty of the country.

"Soldiers and civilians of Pakistan have made sacrifices for this country and their sacrifices demand that we give a befitting reply to terrorists and those who aid and facilitate them," Asif said.

Pakistan released a video "confession" of Jadhav, in which he accepted that he was a former India Navy officer.

Sushma Swaraj warns Pakistan

India has warned Pakistan that the death sentence handed down to Jadhav would hamper bilateral ties. The matter was taken up in Parliament on Tuesday, where MEA Sushma Swaraj said, "I would caution the Pakistan government to consider the consequences to our bilateral relationship if they proceed on this matter."

"There is no evidence of wrongdoing by Jadhav. If anything, he is the victim of a plan that seeks to cast aspersions on India to deflect international attention from Pakistan's well-known record of sponsoring and supporting terrorism," Sushma added.

"Under these circumstances, we have no choice but to regard the sentence, if carried out, as an act of pre-meditated murder. The sentence by the Pakistani Military Court was based on concocted charges."

"Let me state clearly that the government and the people of India would view very seriously the possibility that an innocent Indian citizen is facing death sentence in Pakistan without due process and in violation of basic norms of law, justice and international relations. I would caution the Pakistan government to consider the consequences for our bilateral relationship if they proceed on this matter," she added.

Swaraj also criticised the method used to sentence Jadhav calling it a "farce". "A Pakistan military court awarding the death sentence tells us a lot about the farcical nature of the alleged proceedings which have led to indefensible verdict against an innocent kidnapped Indian," she added.

Parliament was united in its response in condemning Pakistan's move against Jadhav on Tuesday, with multiple MPs from different parties demanding action to save the Indian national.